Modern computing systems can include a variety of communication devices that send and receive data. Examples of communication devices include parallel interface devices and serial interface devices such as the universal serial bus (USB). USB is an industry protocol designed to standardize the interfaces between computer devices for communication and supplying electrical power. The USB protocol has enjoyed widespread adoption in nearly every computing device, and has received tremendous support in terms of technology development with well-established intellectual property (IP) portfolios and standardized software infrastructure.
The standard USB2 specification uses 3.3 Volt analog signaling for communications between the two USB2 ports. The 3.3 Volt signal strength tends to introduce integration challenges because some advanced semiconductor processes are moving towards a very low geometry leading to the gate oxide of a CMOS transistor no longer able to tolerate higher voltages, such as 3.3 Volt. In addition, the standard USB2 specification results in relatively high levels of power consumption at both idle and active states. As a result, USB2 may not be suitable for devices that place stringent specifications on I/O power consumption, such as mobile platforms.